In spite of the relative closeness to earth, the moon still contains many mysteries, namely regarding its mantle formation, crater impacts, and volcanic activities. New analysis of the moon's largest crater offers insights into the moon's formation and other developmental details.
New research is focusing on the largest impact crater on the surface of the moon, known as the South Pole-Aiken basin.
What is the South Pole-Aiken?
The South Pole-Aiken basin is the deepest and oldest impact crater on the moon, covering nearly 25% of the moon's surface. It is up to 5.1 miles deep and over 1,500 miles across. It is thought to have been formed about 4.3 billion years ago.
Science Alert reports that experts are studying the material that was emitted from the basin using radioactive thorium. This is helping to sharpen the timeline of the development of the moon's mantle. Studying the crater can explain many things about the lunar structure before the impact.
A team of researchers, lead by planetary geologist Daniel Moriarty of NASA's Goddard Space Flight Center, shared the significance of the findings in that they shed light on the moon's formation and evolution.
New Theories Emerge
The moon's thorium is believed to have been settled up to 4.5 billion years ago during the Lunar Magma Ocean, Science Alert reports. The theory is that the moon was covered with a layer of molten rock.
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The basin is facing the far end of the moon, the part that doesn't face earth. Therefore, its placement has made it less assessable for study compared to the near side of the moon that does face earth. The near side has many dark splashes and also lunar maria due to ancient volcanic activity from inside of the moon. The far side of the moon is much paler, by comparison, and has many more craters.
One of the new theories that have emerged from new analysis is that the impact of the South Pole-Aiken dug out thorium and splattered it out on the near side of the moon. This suggests that the layer of thorium was distributed around the whole moon, not just on the near side. The impact of the South Pole-Aiken also indicated that the composition of the moon's upper mantle layer was not only thorium but perhaps other material as well.
While many of the splattered material from the impact have been covered throughout 4 billion years, some of the thorium inserts were discovered and may be studied further in the future.
Research Continues
"Formation of the South Pole-Aitken Basin is among the most ancient and important events in lunar history," the researchers wrote.
They added: "As we enter into a new age of international and commercial lunar exploration, these mantle materials at the lunar surface must be considered amongst the highest-priority targets for the advancement of planetary science."
